Hitherto, there have been installed, in a construction, for example, a building, a ventilation apparatus configured to take air outside the construction into an indoor space so as to exhaust indoor air out of the construction so as to keep an indoor condition comfortable, an air-conditioning apparatus configured to heat or cool the indoor air and supply the heated or cooled air again to the indoor space so as to keep an indoor temperature at a predetermined temperature, and an air-conditioning system control apparatus configured to control the ventilation apparatus and the air-conditioning apparatus described above.
For example, the air-conditioning system control apparatus described above determines activation and stop of the ventilation apparatus in accordance with detection data obtained by a carbon dioxide concentration detection sensor included in the ventilation apparatus (see, for example, Patent Literature 1).